KR101564107B1 - Method and apparatus for controlling sleep mode operation in a communication system - Google Patents

Abstract

The present invention relates to a method and apparatus for controlling a sleep mode operation of a mobile terminal in a communication system. The sleep mode operates according to a sleep cycle including a sleep interval corresponding to the awake state and a sleep interval corresponding to the sleep state. When there is data transmission between the subscriber station and the base station during the listening interval, the subscriber station starts a predetermined timer, receives downlink (DL) data from the base station during the listening interval, Upon receiving the control information indicating the timer, the timer is restarted. The listening interval is maintained until the timer expires, and the UE transitions to the sleep interval when the timer expires.

Sleep mode, awake mode, timer

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for controlling a sleep mode operation in a communication system,

The present invention relates to a communication system, and more particularly, to a method and apparatus for controlling a sleep mode operation for a mobile terminal.

2. Description of the Related Art Generally, a communication system is being developed to provide a service capable of transmitting and receiving high-speed large-capacity data to users. A typical example of a communication system is an Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system. In the IEEE 802.16e communication system, a normal mode is a state in which communication is always maintained between a mobile station (MS) and a base station (BS) .

In the IEEE 802.16e communication system, the MS monitors a downlink (DL) to check whether data is received from the BS. At this time, even if there is no data to be transmitted to the MS by the BS, power consumption of the MS occurs because the MS monitors the downlink.

Meanwhile, since the IEEE 802.16e communication system considers the mobility of the MS, the power consumption of the MS is an important factor for the overall performance of the system and affects the mobility of the MS. Accordingly, as a method for minimizing the power consumption of the MS, an awake mode corresponding to a sleep mode (sleep mode) and a sleep mode between the MS and the BS has been proposed.

1 shows an operation for performing an operation for a sleep mode of a communication system.

1, the MS 100 is in an awake mode and transmits a MOB_SLP-REQ (MOBILE SLeeP REQuest) message to the BS 110 in order to transition to a sleep mode (step 101). Upon receiving the MOB_SLP-REQ message, the BS 110 determines whether to allow the MS 100 to perform a mode transition to the sleep mode in consideration of the BS 100 and the MS 100, And transmits a MOB_SLP-RSP (MOBILE SLeeP ReSPonse) message to the MS 100 correspondingly (step 103). The MOB_SLP-RSP message includes a listening interval parameter indicating a listening window. If there is data to be transmitted from the BS 110 to the MS 100 in the listening interval of the sleep mode, the BS 110 transmits the MOB_TRF-IND including the identifier of the MS 100 to the MS 100 during the listening interval. (MOBILE TRaFfic INDICATION) message.

In the meantime, instead of the BS 110 responding to the sleep mode request (transition to sleep mode) of the MS 100, the BS 110 may first respond to the MS 100 in an unsolicited manner, The BS 110 sends a MOB_SLP-RSP message without first receiving the MOB_SLP-REQ message of the MS 100, thereby requesting the MS 100 to enter the sleep mode.

Upon receiving the MOB_SLP-RSP message from the BS 110, the MS 100 starts a sleep mode operation according to the MOB_SLP-RSP message. At this time, the MS 100 performs the sleep mode operation according to the listening interval parameter included in the MOB_SLP-RSP message. If there is data to be transmitted from the MS 100 to the BS 110 while the MS 100 is operating in the sleep mode, the MS 100 can transition from the sleep mode to the awake mode.

If there is no data to be transmitted to the MS 100, the BS 110 transmits an MOB_TRF-IND message that does not include the identifier of the MS 100 in the sleep interval of the sleep mode (step 105). Since the MOB_TRF-IND message does not correspond to the MS 100, the MOB_TRF-IND message includes a negative indication for the MS 100. [ After decoding the MOB_TRF-IND message, the MS 100 confirms that the identifier of the MS 100 is not included and continues to maintain the sleep mode.

When there is data to be transmitted to the MS 100 by the BS 110, that is, a protocol data unit (PDU) for the MS 100 is provided from the network, the BS 110 transmits the identifier of the MS 100 The MOB_TRF-IND message including the MOB_TRF-IND message is transmitted (step 107). Since the MOB_TRF-IND message corresponds to the MS 100, the MOB_TRF-IND message is a positive indication for the MS 100. After decoding the MOB_TRF-IND message, the MS 100 confirms that the identifier of the MS 100 is included and transitions to the awake mode to receive data from the BS 110. [

After the data transmission / reception between the MS 100 and the BS 110 is completed, the MS 100 and the BS 110 exchange the MOB_SLP-REQ message and the MOB_SLP-RSP message to perform a mode transition to the sleep mode again . At this time, since the MOB_SLP-REQ message and the MOB_SLP-RSP message are exchanged for the mode transition to the sleep mode, unnecessary messages are transmitted. This wastes resources of uplink (UL) and downlink (downlink) and consumes power. The MS 100 also has to perform bandwidth ranging by transmitting a BW-REQ (Bandwidth REQuest) message in order to allocate a bandwidth for transmitting an additional MOB_SLP-REQ message to the BS 110, There is a problem that the time for the mode transition to the sleep mode is delayed.

Meanwhile, the MOB_SLP-REQ message includes a power saving class type (Power_Saving_Class_Type) field and a traffic triggering flag (Traffic_Triggered_Wakening_Flag, hereinafter referred to as TTWF). The power saving class type field is used to define one of the following types.

1) Type 1: A class that follows the conventional sleep mode operation. That is, the MS transitions to the awake mode when the data transmission / reception occurs in the listening interval or when the MOB_TRF-IND message including the positive indication is received.

2) Type 2: It has a fixed sleep interval, performs data transmission / reception in the listening interval, and performs data transmission / reception in the next sleep interval after the fixed sleep interval.

3) Type 3: In Type 1 and Type 2, if the MS does not receive a mode change request message, the MS continuously maintains the sleep mode, while Type 3 performs one sleep mode operation, that is, Means a class that exits mode. It is mainly used for management messages or multicast traffic.

The TTWF field applies only to Type 1 power saving classes. More specifically, TTWF is used when the MS desires to maintain the sleep mode even if data is generated during the listening interval.

As an example, if 'TTWF = 0', the MS transmits and receives data during the listening interval, and transitions to the sleep mode again at the end of the listening interval, that is, at the beginning of the sleep interval. When the BS wants to transmit a Medium Access Control (MAC) SDU (Service Data Unit) for the corresponding power saving class during the listening interval, or when the MS transmits a BW-REQ message for the connection for the corresponding power saving class, The MS receives a MOB_TRF-IND message including a positive indication from the BS, i.e., an identifier of the MS, the MS exits the sleep mode and transitions to the awake mode. Otherwise, the MS may terminate the sleep mode through a transaction of the MOB_SLP-REQ message and the MOB_SLP-RSP message.

On the other hand, when 'TTWF = 1', the MS receives a PDU (Packet Data Unit) from the BS during the listening interval, or transmits a management message instructing the end of the sleep mode, for example, an MOB_SLP- Upon receiving the DL Sleep Control Extended Subheader, the MS exits the sleep mode and transitions to the awake mode. Also, when transmitting a management message, i.e., a MOB_SLP-REQ message, a bandwidth request message, or an uplink sleep control header, to the BS, in which data to be transmitted in the MS occurs or an end of the sleep mode is transmitted to the BS, And transits to the awake mode. In other words, when 'TTWF = 1', when the traffic data or the corresponding management message is generated during the listening interval, the MS transits to the awake mode.

As described above, the power saving class Type 1 in the sleep mode operation of the IEEE 802.16e communication system is used for maintaining or deactivating the sleep mode when the MS receives the MAC SDU in the listening interval from the BS according to the TTWF do. However, in the prior art, when the MS desires to maintain the sleep mode, it is not clearly defined when the sleep mode is to be switched to the sleep mode after the listening interval ends. Also, the TTWF is initially set in the MOB_SLP-REQ message and the MOB_SLP-RSP message transmitted and received by the MS and the BS. However, there may occur a situation in which the value of TTWF is changed while performing the sleep mode operation. In this case, a specific operation for changing the value of TTWF is required.

Another problem is that when the UE and the BS simultaneously request the sleep mode to each other, that is, the UE transmits the MOB_SLP-REQ message and the MOB_SLP-RSP message before the base station recognizes the MOB_SLP-REQ , The UE can not know whether the MOB_SLP-RSP message received from the base station is transmitted in response to the MOB_SLP-REQ message or not. This may lead to a mismatch of the sleep mode related parameters between the terminal and the base station, which may lead to a malfunction of the sleep mode. Since the sleep mode operation of the conventional IEEE 802.16e does not refer to such a situation at all, only the 'Sleep_Approved' field included in the MOB_SLP-RSP message and indicating whether the activation or deactivation request of the corresponding power saving class is approved, The base station may mistakenly accept the request as it is. To prevent this, the UE must compare all the parameters included in the MOB_SLP-RSP message with each other to match the values requested by the UE.

Another problem is that, when a negotiation is made between the MS and the BS to inform the presence or absence of downlink traffic through the MOB_TRF-IND message, that is, in the MOB_SLP-REQ / RSP message, the power saving class Type 1 IND_required 'field indicating that the BS transmits at least one MOB_TRF-IND message to the UE for every listening interval is set to' 1 ', the BS must transmit the MOB_TRF-IND message during the listening interval of the UE . Therefore, even if there is no downlink traffic to be transmitted to the awake terminals during the listening interval, the base station transmits a MOB_TRF-IND message, thereby wasting resources. In addition, when the base station does not send the MOB_TRF-IND message, the terminal can not distinguish whether the base station has not transmitted the MOB_TRF-IND message or the base station has not received the MOB_TRF-IND message, , The UE determines that it has not received the MOB_TRF-IND message and wakes up from the sleep mode.

The present invention provides a method and apparatus for controlling a sleep mode operation in a communication system.

The present invention provides a sleep mode operation control method and apparatus for reducing resource waste in a communication system.

The present invention provides a sleep mode operation control method and apparatus for reducing power consumption of an MS in a communication system.

In a communication method of a terminal (MS) in a communication system, a method proposed by the present invention is a method in which when the terminal receives at least one of first signaling information and data for instructing data transmission on a first allocated resource from the base station, The method comprising the steps of: starting a timer for a listening interval corresponding to a listening state; and receiving, when the terminal receives second signaling information indicating data transmission on a second allocated resource from the base station, And maintaining the listening state by extending the listening interval until the timer expires; and transitioning to a sleep state when the timer expires.
According to another embodiment of the present invention, there is provided a method comprising: A method for controlling communication of a terminal (MS) in a communication system, the method comprising the steps of: when a base station transmits at least one of first signaling information and data indicating a data transmission on a first allocated resource, The base station restarts the timer to extend the listening interval if the base station transmits second signaling information indicating a data transmission on a second allocated resource to the terminal, Determining that the terminal is in the listening state by extending the listening interval until the timer expires; determining that the terminal has transitioned to a sleep state when the timer expires; .
An apparatus according to a preferred embodiment of the present invention comprises: A terminal apparatus in a communication system, comprising: a terminal for receiving a first signaling information and data for instructing data transmission on a first allocated resource from a base station; and a timer for a listening interval corresponding to the listening state, And a transceiver for maintaining the listening state by extending the listening interval until the timer expires and transiting to a sleep state when the timer expires.
According to another embodiment of the present invention, there is provided an apparatus comprising: A base station apparatus for controlling communication of a mobile station (MS) in a communication system, the base station apparatus comprising: a base station for communicating at least one of first signaling information and data for instructing data transmission on a first allocated resource, The base station restarts the timer to extend the listening interval if the base station transmits second signaling information indicating data transmission on a second allocated resource to the terminal, The controller determines that the terminal is in the listening state by extending the listening interval until the timer expires and determines that the terminal transitions to the sleep state when the timer expires; And a transceiver for exchanging data and messages with the terminal under control.

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The present invention proposes a sleep mode operation control method that considers power consumption reduction in a communication system. It has an advantage of reducing the power consumption by controlling the sleep mode operation between the MS and the BS by operating the timer proposed in the present invention.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The terms used below are defined in consideration of the functions of the present invention and can be changed according to the intention or custom of the user, the operator. Therefore, the definition should be based on the contents throughout this specification.

In a preferred embodiment of the present invention, a sleep mode operation control method and apparatus in a communication system is proposed. Hereinafter, the sleep mode operation control method will be described by taking IEEE 802.16e and a communication system based thereon as an example. However, the sleep mode operation control proposed in the preferred embodiment of the present invention may be applied to other similar communication systems Of course it is possible. Also, in this specification, an operation for controlling one sleep mode operation by one MS and a BS in a communication system is described. However, it goes without saying that the sleep mode operation control according to the embodiments described below is applicable even when there are a plurality of MSs in the communication system.

The MS and the BS exchange the MOB_SLP-REQ (MOBILE SLeeP REQuest) message and the MOB_SLP-RSP (MOBILE SLeeP ReSPonse) message for the mode transition to the sleep mode. The sleep mode includes a sleep interval and a listening interval. When the MOB_SLP-REQ message and the MOB_SLP-RSP message are transmitted and received, the time of entry into the sleep mode, the length of the sleep interval, and the length of the listening interval are determined. A state in which power is consumed due to data transmission / reception or standby state between the MS and the BS is defined as an awake state, and a state in which the MS does not transmit / receive data with the BS in order to reduce power consumption is a sleep state Is defined. The awake state and the sleep state all correspond to the sleep mode. That is, the sleep mode is divided into an awake state corresponding to a listening interval and a sleeping interval corresponding to a sleep interval (i.e., a period other than the listening interval).

The MS may wake up in a listening interval that has been negotiated with the BS. However, if the pre-negotiated listening interval is not included in the first frame in the super frame structure including a plurality of frames, the MS may wake up in the first frame as well as the pre-negotiated listening interval.

Similarly, in the case of a communication system using a superframe structure, a basic unit representing an operation unit and a listening interval transited to the sleep state of the MS becomes a superframe. That is, the MS can transition from the first frame of the superframe to the sleep state, and can also wake up from the listening interval in the first frame of another superframe. Even if the MS has not transitioned from the first frame of the superframe to the sleep state, the awake at the listening interval must be the first frame of the other superframe.

In the embodiments of the present invention, data transmission / reception between the MS and the BS is performed after the MS enters the sleep mode and is in the sleep interval and is awake in the listening interval and receives the MOB_TRF-IND message from the BS (MOBILE TRAFfic INDICATION) When it does not happen, it proposes an operation to transit to the sleep state again.

In the present specification, data transmission / reception between the MS and the BS will be described by transmitting data to the MS after the BS transmits the MOB_TRF-IND message to the MS. However, it goes without saying that the data transmission method for reducing power consumption proposed in the embodiments of the present invention is also applicable to the case of transmitting and receiving data without transmitting the MOB_TRF-IND message.

First, the messages for supporting the operation of the sleep mode and the awake mode in the IEEE 802.16e communication system will be described.

(1) MOB_SLP-REQ message

The MOB_SLP-REQ message is transmitted to the BS when the MS is in the awake mode and wants to perform a mode transition to the sleep mode. The MOB_SLP-REQ message includes parameters required for a mode transition of the MS to the sleep mode, that is, information elements (IEs). The format of the MOB_SLP-REQ message is shown in Table 1 same.

As shown in Table 1, the MOB_SLP-REQ message includes the following IEs.

'Management Message Type' is information indicating the type of a transmitted message, and when the message type is '50', it means an MOB_SLP-REQ message. 'Number of Classes' indicates the number of power saving classes to be included in the MOB_SLP-REQ message. "Definition" indicates whether to indicate a definition of a new power saving class or a definition of an existing class. 'Operation' indicates whether the power saving class is activated or deactivated. The 'Power_Saving_Class_ID' represents an identifier for indicating a power saving class that indicates a current operation. The start frame number (start_frame_number) indicates a time point at which the corresponding power saving class is activated, that is, a start frame number for the first sleep interval. The 'Power_Saving_Class_Type' indicates the type of the corresponding power saving class. Here, the type of the corresponding power saving class is as follows.

1) Type 1: A class that follows the conventional sleep mode operation. That is, the MS wakes up in an awake mode when data transmission / reception occurs in a listening interval or when a MOB_TRF-IND message including a positive indication is received.

2) Type 2: It has a fixed sleep interval, transmits / receives data in the listening interval, and transmits / receives data in the next scheduled listening interval after the fixed sleep interval.

3) Type 3: If Type 1 and Type 2 do not receive a mode transition request message, the system continues to maintain the sleep mode, whereas Type 3 performs one sleep mode operation, that is, after one sleep period, Which means a class that It is mainly used for management messages or multicast traffic.

In addition, 'Direction' indicates whether it is an uplink or a downlink. 'Traffic_Triggered_Wakening_Flag (TTWF)' applies only to Type 1, which is the type of the corresponding power saving class indicated by Power_Saving_Class_Type. That is, TTWF is used when the MS maintains the sleep mode as in Type 2 in the power saving class of Type 1 and desires to transmit / receive data during the listening interval.

The 'Initial-sleep Window' represents the initial length of the sleep interval, and the 'Listening Window' represents the required length of the listening interval (Assigned Duration). The length of the sleep interval is doubled at the end of the listening interval. The maximum length of the sleep interval is the 'final-sleep window base' and the 'final-sleep window' the maximum length of the sleep interval is determined as' (final-sleep window base) * 2 '(final-sleep window exponent)'. Also, 'Number of Connection IDs (CIDs) (Number_of_Sleep_CIDs)' indicates the number of unicast CIDs corresponding to the power saving class.

(2) MOB_SLP-RSP message

The MOB_SLP-RSP message is transmitted from the BS to the MS to indicate whether the MS should allow the mode transition to the sleep mode in consideration of the situation of the BS and the MS, or may be transmitted from the BS to the MS in order to indicate an unsolicited instruction. . The MOB_SLP-RSP message includes parameters required for the MS to operate in the sleep mode, that is, IEs. The format of the MOB_SLP-RSP message is as shown in Table 2 below.

The MOB_SLP-RSP message is also transmitted based on the basic CID of the MS.

'Management Message Type' is information indicating the type of a message to be transmitted, and when the message type is 51, it means the MOB_SLP-RSP message. The 'length of data (Length_of_Data)' indicates the number of bytes of the power saving class. 'Sleep_Approved' indicates whether the activation or deactivation request of the corresponding power saving class of the MS is approved. If the value of Sleep_Approved is '1' and the value of 'Operation' is '1' (activation), 'Start_frame_number' is included. If the value of Sleep_Approved is' 1 'and' Definition 'is' 1', 'Power_Saving_Class_Type', 'Direction', 'initial-sleep window', 'listening window', ' final-sleep window exponent ',' MOB_TRF-IND required ', and' TTWF '. Here, 'MOB_TRF-IND required' is applied only to the power saving class Type 1, and indicates that the BS should transmit at least one MOB_TRF-IND message to the MS for each listening interval.

(3) MOB_TRF-IND message

The MOB_TRF-IND message is transmitted from the BS to the MS during the listening interval and is used to indicate whether or not there is data to be transmitted to the MS by the BS. Unlike the MOB_SLP-REQ message or the MOB_SLP-RSP message, the MOB_TRF-IND message is transmitted in a broadcasting or multicasting manner. The format of the MOB_TRF-IND message is shown in Table 3 below.

As shown in Table 3, the MOB_TRF-IND message is used to indicate whether there is data to be transmitted to the MS by the BS. The MS receives the MOB_TRF-IND message during the listening interval, It is determined whether to transition to the awake mode or keep the sleep mode.

When the MS transitions to the awake mode, the MS confirms frame synchronization. At this time, if the frame sequence number expected by the MS is not correct, the MS may request retransmission of the lost data in awake mode. On the other hand, when the MS does not receive the MOB_TRF-IND message or receives the MOB_TRF-IND message during the listening interval, the received MOB_TRF-IND message indicates a negative indication, for example, when the MS indicates that there is no data to be received , The MS maintains the sleep mode.

The MOB_TRF-IND message includes a plurality of IEs as described below.

'Management Message Type' is information indicating the type of a message to be transmitted, and when the message type is 52, it means an MOB_TRF-IND message. 'FMT' indicates whether the MOB_TRF-IND message uses SLPID (SLeeP IDentifier) bitmap format or SLPID format.

(4) Downlink Sleep Control Extended Subheader

The downlink sleep control extension header is transmitted from the BS to the MS to activate or deactivate the power saving class. The format of the downlink slip control extension header is as shown in Table 4 below.

Since the IEs of the downlink slip control extension header are as described above, a detailed description thereof will be omitted here.

Hereinafter, the sleep mode operation control according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 5. FIG.

2 is a diagram illustrating an operation for a BS to transmit data in a communication system according to an embodiment of the present invention.

Referring to FIG. 2, the BS and the MS exchange a MOB_SLP-REQ message and a MOB_SLP-RSP message for a mode transition to a sleep mode to determine a time to enter a sleep mode, a length of a sleep interval and a length of a listening interval, The MS enters the sleep mode at the determined time. Since the operation to enter the sleep mode is the same as that of the conventional art, the description thereof will be omitted here.

In FIG. 2, the length of the sleep interval is determined to be 8 frames and the length of the listening interval is 2 frames through transmission / reception of the MOB_SLP-REQ message and the MOB_SLP-RSP message between the MS and the BS. The BS recognizes that the MS is in the sleep interval of the sleep mode from frames # 0 to # 7 that are not shown. Upon entering Frame # 8 (201), the BS recognizes that it is in the listening interval and transmits an MOB_TRF-IND message including the MS's identifier in Frame # 8 (203) to indicate that there is data to be transmitted to the MS. . The BS transmits data to the MS immediately after transmitting the MOB_TRF-IND message (205). After the MS recognizes the MOB_TRF-IND message, if there is data to be transmitted to the BS, the MS transmits the data to the BS during the listening interval (step 205).

Meanwhile, the MS starts the timer T1 when there is no more data to be received from the BS and there is no data to be transmitted to the BS. The timer T1 is used to recognize when the MS does not have data to receive from the BS and the MS also has no data to transmit to the BS. Also, the MS can be used to recognize when there is no data to be received from the BS, but the MS has data to be transmitted to the BS. It can also be used by the MS to acknowledge when there is data to be received from the BS but there is no data to be transmitted by the MS to the BS. Therefore, the timer T1 is reset to 0 and restarted when data transmission / reception between the BS and the MS occurs. Thereafter, when the BS completes the data transmission to the MS in frame # 11 or the data reception from the MS to the BS is completed, in the frame # 12, the BS no longer has the data to be transmitted to the MS and the data to be received from the MS to the BS . Therefore, the MS increases the timer T1 for entering the sleep state from 1 to every frame starting from frame # 12. If the threshold value of the timer T1 is set to 4 frames, the timer T1 is incremented by 1 from the frame # 12 to the frame # 15.

When there is no data to be transmitted to the MS until the timer T1 reaches the threshold value of 4 and there is no data to be received from the MS to the BS, the timer T1 is expired (207) Enters the sleep mode. That is, the MS operates in the sleep mode from the next frame (frame # 16) in which the value of the timer T1 becomes the threshold value. The BS may also have a timer T1 operating in the same manner as in the MS, thus knowing whether the MS is operating in the sleep mode or in the awake mode.

Then, the next data transmission / reception will be performed in the next listening interval. Since the operation in the next listening interval is the same as that described above, the description thereof will be omitted here. As shown in the example, if the TRF-IND message including a negative indication is received in the next listening interval, Frame # 18 (209), the MS continues to maintain the sleep mode.

3 is a diagram illustrating an operation for an MS to transmit data in a communication system according to an embodiment of the present invention.

Referring to FIG. 3, the BS and the MS exchange a MOB_SLP-REQ message and a MOB_SLP-RSP message for a mode transition to a sleep mode to determine a time to enter a sleep mode, a length of a sleep interval and a length of a listening interval, The MS enters the sleep mode at the determined time. Since the operation to enter the sleep mode is the same as that of the conventional art, the description thereof will be omitted here.

In FIG. 3, the length of the sleep interval is 8 frames and the length of the listening interval is 2 frames through transmission and reception of the MOB_SLP-REQ message and the MOB_SLP-RSP message between the MS and the BS. The MS recognizes that the frame # 0 to the frame # 7, which are not shown, are the sleep periods of the sleep mode, and operate in the sleep mode. Upon entering Frame # 8 (301), the MS acknowledges that it is in the listening interval and awakes, and transmits an uplink bandwidth allocation request (UL_BW-REQ) message to the BS in Frame # 8 (303).

The MS then transmits the data to the BS (305). If there is data to be received from the BS in the listening interval, data is received from the MS in the listening interval (305). The MS completes transmission and reception of data, and simultaneously operates the timer T1 after resetting the timer T1 to zero.

The timer T1 is used to recognize when the MS does not have data to receive from the BS and the MS also has no data to transmit to the BS. Also, the MS may be used to recognize when there is no data to be received from the BS, but the MS has data to send to the BS. It can also be used by the MS to acknowledge when there is data to be received from the BS but there is no data to be transmitted by the MS to the BS. Therefore, the timer T1 is restarted to 0 when data transmission between the BS and the MS occurs.

When data transmission from the MS to the BS is completed in frame # 11 or data reception from the BS to the MS is completed, in the frame # 12, there is no data to be transmitted to the BS and data to be received from the BS to the MS. Therefore, the MS increases the timer T1 for entering the sleep state from 1 to every frame starting from frame # 12. If the threshold value of the timer T1 is set to 4 frames, the timer T1 from the frame # 12 to the frame # 15 increases from 1 and operates.

When there is no data to be transmitted to the BS until the MS reaches the threshold of 4, which is the threshold value of the timer T1, and there is no data to be received from the BS to the MS, the timer T1 expires (307) Mode. Then, the next data transmission / reception will be performed in the next listening interval. Since the operation in the next listening interval is the same as that described above, the description thereof will be omitted here. As shown in the example, when the TRF-IND message including the negative indication is received in the next listening interval, frame # 18 (309), the MS continues to maintain the sleep mode.

4 is a diagram illustrating an operation of the MS related to the sleep mode in the communication system according to the embodiment of the present invention.

Referring to FIG. 4, in step 401, the MS exists in a sleep interval of the sleep mode, and enters a listening interval to monitor whether data is received from the BS. Upon entering the listening interval, the MS receives and decodes the MOB_TRF-IND message from the BS in step 403, and proceeds to step 405. In step 405, the MS determines whether the MS identifier is included in the MOB_TRF-IND message. If the identifier of the MS is included, the process proceeds to step 409, and if the identifier of the MS is not included, the process proceeds to step 407. In step 409, the MS enters an awake state, receives data from the BS, and proceeds to step 411. In step 407, the MS determines whether there is data to be transmitted to the BS in the uplink buffer. If there is data to be transmitted, the MS proceeds to step 409. In step 409, the MS transmits data to the BS and proceeds to step 411.

In step 411, the MS resets the timer T1 to 0 as soon as data transmission / reception between the MS and the BS is completed, and proceeds to step 413. In step 413, the MS determines whether there is data to be transmitted / received in the next frame. If it is determined in step 415 that there is no data to be transmitted to the BS and no data to be received from the BS to the MS after completion of data transmission / reception between the MS and the BS, the MS increments the timer T1 by 1 and proceeds to step 419 do. In step 419, the MS determines whether the timer T1 has reached a preset threshold value. In step 421, the MS transitions to the sleep mode and terminates. If there is data to be transmitted to the BS in step 415 or data to be received from the BS to the MS, the MS returns to step 409 to perform data transmission / reception again. On the other hand, if there is no data to be transmitted to the BS in step 407, the MS proceeds directly to step 421 and transitions to the sleep state and terminates.

5 is a diagram illustrating a sleep mode related operation of a BS according to an embodiment of the present invention.

Referring to FIG. 5, in step 501, the BS determines whether there is data to be transmitted to the MS. If there is data to be transmitted to the MS, the BS proceeds to step 503, and if there is no data to transmit, In step 503, the BS includes the MS identifier in the MOB_TRF-IND message and proceeds to step 505. In step 505, the BS waits for a listening interval and proceeds to step 507 when it reaches a listening interval. In step 507, the BS transmits a MOB_TRF-IND message to the MS, and proceeds to step 509. In step 509, the BS is in an awake state and transmits / receives data to / from the MS.

In step 511, the BS completes data transmission to the MS, and simultaneously resets (resets) the timer T1 from 0, and proceeds to step 513. In step 513, In step 513, the BS determines whether there is data to be transmitted / received in the next frame for data transmission / reception between the BS and the MS. If it is determined in step 515 that there is no data to be transmitted to the MS, step 517 is performed. In step 517, the BS increments the timer T1 by 1 and proceeds to step 519. [ In step 519, the BS determines whether a preset threshold value of the timer T1 has been reached. If the timer T1 has reached the threshold value, the BS proceeds to step 521. In step 521, the BS recognizes that the MS transits to the sleep state and ends the process.

If it is determined in step 501 of FIG. 5 that there is no data to be transmitted to the MS, the BS proceeds to step 523. In step 523, the BS waits for a listening interval and proceeds to step 525 when it reaches the listening interval. In step 525, the BS transmits an MOB_TRF-IND message that does not include the identifier of the MS, and proceeds to step 527. In step 527, the BS waits for the uplink traffic in the listening interval and the subsequent listening interval, and proceeds to step 529. If it is determined in step 529 that there is no data reception from the MS to the BS, In step 531, the BS determines whether there is data to be transmitted or received. If it is determined in step 533 that the listening interval is terminated, the BS proceeds to step 521 to recognize that the MS has transitioned to the sleep state and ends. If the listening interval is not terminated in step 533, the BS returns to step 529 to wait for the uplink traffic from the MS to be received.

On the other hand, if the MS has received data from the MS in step 529, the BS proceeds to step 511.

Although not shown, a sleep mode operation control method using the timer T2 and the timer T3 will be further described.

The BS and the MS transmit and receive the MOB_SLP-REQ message and the MOB_SLP-RSP message in order to perform a mode transition to the sleep mode when the data transmission and reception occur for the first time, and determine the time to enter the sleep mode, the length of the sleep interval, And the MS enters the sleep mode according to the determined parameter. Since the operation to enter the sleep mode is the same as that of the conventional art, the description thereof will be omitted here. After entering the sleep mode and reaching the listening interval, the BS transmits the MOB_TRF-IND message to the MS and then transmits the data to the MS. At this time, the timer T2 and the timer T3 operate. A timer T2 for the downlink is used to determine whether the MS has no data to receive from the BS or that the BS has no data to send to the MS. A timer T3 for the uplink is used to determine if the MS has no data to send to the BS or if the BS has no data to receive from the MS.

The timer T2 and the timer T3 are reset to 0 at the same time that data transmission / reception is completed, and then start to operate again. If there is no data to be received from the BS by the MS or if there is no data to be transmitted to the MS in each frame, the timer T2 increases by 1 and operates up to a predetermined threshold value. Similarly, if there is no data to be transmitted to the BS by the MS or if there is no data to be received from the MS at every frame, the timer T3 increases by 1 and operates up to a predetermined threshold value. If data transmission / reception is not performed until both the timer T2 and the timer T3 reach the threshold value, the MS immediately enters a sleep mode to be in a sleep mode, and the BS recognizes that the MS has made a mode transition to a sleep mode. The BS may have timers T2, T3 operating in the same manner as in the MS, so that it can accurately know whether the MS is operating in the sleep mode or in the awake mode.

In the second exemplary embodiment, the sleep mode operation scheme described in the first exemplary embodiment is referred to as a power saving class type (hereinafter, referred to as " 0 ") in which the Traffic_Triggered_Wakening_Flag (hereinafter referred to as TTWF) included in the MOB_SLP- Power_Saving_Class_Type) 1 will be described.

Here, TTWF is used when the MS desires to maintain the sleep state even if data is generated in the listening interval. In the sleep mode, an operation of performing data transmission / reception during a fixed listening interval while repeating a sleep interval and a listening interval, and an operation of varying a listening interval, i.e., an operation of continuously maintaining a listening interval during data transmission / reception can do. Hereinafter, the two operations will be referred to as 'new sleep mode' operation.

Additional parameters are defined for control of the new sleep mode operation. The parameter is added to the REG-REQ (REGistration REQuest) message and the REG-RSP (REGistration RSPonse) message, which are transmitted and received at the time of entering the network with the BS. The parameter is referred to as a Variable Listening Interval Indicator (VLII), and can be expressed as shown in Table 5, for example.

If the VLII is omitted in the REG-REQ message and the REG-RSP message, it is regarded as a default value '0'. Also, if the VLII is set to '0' in the messages, the new sleep mode operation can not be performed and the basic listening interval has a fixed period. Operation according to VLII will be described in detail below.

In the case of a BS capable of supporting a new sleep mode operation, it is checked whether the MS can perform a new sleep mode operation. If the MS can not perform a new sleep mode operation, the BS transmits the REG-RSP message without including the VLII parameter, or sets the VLII parameter to '0' when transmission of the MOB_SLP-RSP message is required.

If the MS can perform the new sleep mode operation, the MS checks whether the BS can support the new sleep mode operation. If the BS can not support the new sleep mode operation, the MS transmits the RNG-REQ message without including the VLII parameter, or sets the VLII parameter to '0' when transmission of the MOB_SLP-REQ message is required .

Here, the VLII parameter may be transmitted / received using a message other than the REG-REQ message or the REG-RSP message, for example, a Subscriber Station Basic Capability REQuest (SBC-REQ) message or an SBC-RSP (Subscriber Station Basic Capability RSPonse) message.

On the other hand, for the new sleep mode operation of the power saving class type 1 with TTWF = 0, the following modified messages are used.

(1) MOB_SLP-REQ message

The MOB_SLP-REQ message is transmitted to the BS when the MS is in the awake state and wants to transit to the sleep state. The format of the MOB_SLP-REQ message proposed in the embodiment of the present invention is shown in Table 6 below.

As shown in Table 6, the MOB_SLP-REQ message further includes a VLII parameter in addition to the IE fields of Table 1. [ The VLII parameter only applies if TTWF is set to '0'. That is, if the MS fails to perform a new sleep mode, it is set to '0', and the MS is set to '0' even if it can perform a new sleep mode but the BS can not support the new sleep mode.

The VLII parameter has two meanings as follows.

* VLII = 0: This indicates that the MS operates in the basic sleep mode. That is, the MS and the BS perform data transmission and reception during a fixed listening interval with a fixed length of the listening interval. When the listening interval ends, the MS must transition to the sleep state and operate in the next listening interval.

* VLII = 1: Means that the MS operates according to the embodiment shown in FIGS. 2 to 5. That is, the MS and BS perform data transmission and reception during a variable listening interval. That is, the MS and the BS transmit and receive data in the listening interval, and the listening interval is extended when data to be transmitted and received continuously exist. If data transmission / reception is not performed for a certain period of time after data transmission / reception is completed, the MS transits to the sleep state again, and the MS operates in the next listening interval.

(2) MOB_SLP-RSP message

The MOB_SLP-RSP message is transmitted to the MS to indicate whether to permit the mode transition to the sleep mode of the MS in consideration of the situation of the BS and the MS, or is transmitted to the MS to indicate the unsolicited instruction. The parameters required for the MS to operate in the sleep mode are included in the IEs in the MOB_SLP-RSP message, and the format of the MOB_SLP-RSP message proposed in the present invention is as shown in Table 7 below.

As shown in Table 7, the MOB_SLP-RSP message further includes a VLII parameter in addition to the IE fields of Table 2 above. The VLII parameter only applies if TTWF is set to '0'. That is, the VLII parameter is used to indicate whether or not the BS can support the new sleep mode. If the BS can not support the new sleep mode, it is set to '0'. If the BS can support the new sleep mode but TTWF is set to '1', the VLII parameter is set to '0'. If it is determined that the MS can not perform a new sleep mode upon entering the network, the VLII parameter is set to '0'. Even when the MS recognizes that it does not support the new sleep mode at the time of entering the network, the VLII parameter is set to '0' to allow the MS to operate in the existing sleep mode.

The MS and the BS confirm that VLII = 1 is set in the MOB_SLP-REQ message and the MOB_SLP-RSP message, and recognize that both the BS and the MS can operate in the new sleep mode.

At this time, the MS and the BS recognize the transition point to the end point and the sleep state of the variable listening interval proposed in the new sleep mode operation using the following timers.

(1) MS timer for new sleep mode (Timer_in_MS_for_New_SLM): Timer managed by the MS. The timer of the MS starts from the next frame after the end of the listening interval, that is, the listening interval acquired by the MOB_SLP-REQ message and the MOB_SLP-RSP message, which is exchanged between the MS and the BS, and increases by 1 every frame. And is reset each time data is received, thereby substantially extending the listening interval. At this time, if there is no data to be transmitted / received during the listening interval, the MS transitions to the sleep state without operating the timer again. As an example, upon receiving the MOB_TRF-IND message, if the MOB_TRF-IND message confirms that the MS identifier is not included, the MS transits to the sleep state. If there is no data to be transmitted to the BS until the timer reaches the threshold value, that is, until the timer expires, the MS transitions from the listening interval to the sleeping state, until the next listening interval starts, State.

(2) BS timer for new sleep mode (Timer_in_BS_for_New_SLM): Timer managed by the BS. The timer of the BS is incremented by 1 every frame starting from the next frame after the end of the listening interval, i.e., the scheduled listening interval, obtained by the MOB_SLP-REQ message and the MOB_SLP-RSP message exchanged between the MS and the BS, And is reset each time it receives data from the MS, thereby substantially extending the listening interval. If there is no data to be transmitted to the MS until the timer expires, the BS recognizes that the MS has transitioned to the sleep state and transmits the generated data until the MS wakes up in the next listening interval even if data is generated Without buffering.

Here, the count unit of the timers may be time or frame. If the counting unit of the timers is a frame and the threshold is 5 frames, the timers normally expire when no data is received from the counterpart node for 5 frames.

On the other hand, when TTWF = 0 and VLII = 1, in order for the power saving class to be terminated, that is, for the MS to leave the sleep mode, the MOB_SLP-REQ message and the MOB- Deactivation of the downlink sleep control extension header is used.

Further, the MS transits to the sleep state when the timer expires or when there is no data to be transmitted / received. However, if the MS desires to transition to the sleep state before the timer expires, or if the BS wishes to transition the MS to the sleep state, the MS transmits and receives the MOB_SLP-REQ message and the MOB_SLP-RSP message and transitions to the sleep state.

The BS may also use the management message to cause the MS to transition to the sleep state. In this case, the BS sets the management message to an unsolicited indication.

Exceptions in the second embodiment will be described.

1. When the BS receives a BW-REQ message from the MS during the sleep interval.

Even if the MS exists in the sleep state, for example, an urgent situation occurs and data has to be transmitted to the BS, or data to be transmitted from the MS at the beginning of the listening interval has occurred, but a CDMA (Code Division Multiple Access) When a ranging is required or a period from when the BS receives the UL burst grant to the BS is longer than the listening interval, the BW-REQ message can be transmitted to the BS.

The BS determines whether to allow data transmission of the MS in response to the BW-REQ message. If the MS permits data transmission, the BS starts Timer_in_BS_for_New_SLM and waits for data reception from the MS. Likewise, when the BS has allowed the MS to transmit data, that is, when receiving the UL burst grant from the BS, the MS transmits data to the BS through the UL burst, and simultaneously drives the Timer_in_MS_for_New_SLM, And waits for reception.

When the MS described above is present in the sleep state, it is needless to say that the transmission of the BW-REQ message may be performed immediately or may occur in the next listening interval according to the MS's will or selection.

2. The MS does not receive DL-MAP or UL-MAP, which is normal MAP information.

When the MS reaches the listening interval, it starts the Timer_in_MS_for_New_SLM timer and waits for data reception from the BS. The BS transmits the basic MAP (DL-MAP / UL-MAP) to the MS and then transmits the data.

Meanwhile, if there is data to be transmitted / received between the BS and the MS at the end of the listening interval, the MS can transmit / receive data with the BS by extending the listening interval. However, during the Extended Listening Window (ELW), the MS may not receive the base MAP. In this case, the MS can not determine whether or not the BS has transmitted data to the MS, and accordingly, the MS determines that there is no data to be transmitted by the BS and transits to the sleep state.

In this case, the MS resets or temporarily pauses the Timer_in_MS_for_New_SLM timer before transitioning to the sleep state to extend the listening interval. At this time, the MS may reset the Timer_in_MS_for_New_SLM timer only to extend the listening interval only when the BS can not receive only the DL-MAP among the base MAPs.

3. The MS does not receive the SUB-DL / UL-MAP.

The BS transmits up to three SUB-DL-UL-MAPs using a compressed MAP, rather than a basic MAP. That is, the BS can apply different MCS (Modulation and Coding Scheme) levels to up to three SUB-DL-UL-MAPs. The MS may decode only one of up to three SUB-DL-UL-MAPs, or all of them, depending on the channel state. If the MS fails to receive or decode all the SUB-DL-UL-MAPs transmitted by the BS during the listening interval, the MS resets the Timer_in_MS_for_New_SLM timer to extend the listening interval.

In other words, if the MS can not decode the compressed MAP, the SUB-DL / UL-MAP can not also be decoded. Therefore, the MS resets the Timer_in_MS_for_New_SLM timer to extend the listening interval even if the MS fails to decode the compressed MAP transmitted by the BS.

4. The response message is not received for the data transmitted by the BS from the MS.

The BS transmits data to the MS in a communication system employing an ARQ (Automatic Repeat Request) scheme and drives a Timer_in_BS_for_New_SLM timer to wait for a feedback message from the MS. The MS may determine normal reception or abnormal reception of data transmitted by the BS, and may transmit an ACK or NACK message to the BS according to the determination. However, it may happen that the MS fails to transmit an ACK or NACK message to the BS due to poor channel condition or low battery of MS. That is, the BS does not receive an ACK or NACK message indicating normal reception or abnormal reception of data transmitted by the BS to the MS. In this case, the Timer_in_BS_for_New_SLM timer driven by the BS expires.

Also, even if another data to be transmitted to the MS occurs, the BS stops data transmission to the MS since the ACK or NACK message is not received from the MS, and resumes data transmission again in the next listening interval. In other cases, the BS stops data transmission to the MS even though the CQI information through the Channel Quality Indication Channel (CQICH) allocated to the MS is not transmitted to the BS a predetermined number of times. In addition, when the BS allocates the UL resource for the UL burst to the MS and the MS does not transmit the UL burst data to the allocated resource, the BS regards the MS as an abnormal state and transmits it to the MS in the current listening interval The transmission of the data is delayed to the next listening interval even if data is generated.

As a modified embodiment of the present invention, the VLII parameter is included in the TLV encoding format in the MOB_SLP-REQ message and the MOB_SLP-RSP message in the form of IE or TLV Encoding.

For example, the VLII parameter is included in the 'TLV encoded information' IE in the MOB_SLP-REQ message and the MOB_SLP-RSP message as shown in Table 8 below.

As shown in Table 8, 'TLV encoded information' includes a Power Saving Class Identifier (ID) and a VLII for the power saving class identifier.

As another modified embodiment of the present invention, the threshold of the MS's timer for the new sleep mode can be signaled between the BS and the MS. That is, if the MS can perform a new sleep mode operation, a parameter as shown in Table 9 below is included in the REG-REQ message together with the VLII parameter. As an example, the following parameters, namely the Timer_in_MS_for_New_SLM parameter, have a TLV encoding type.

If only the VLII is included in the REG-REQ message and the Timer_in_MS_for_New_SLM is not included, the BS considers the MS to request a default value.

When confirming that the BS requests a default value of Timer_in_MS_for_New_SLM in the REG-REQ message transmitted from the MS, the BS includes a parameter as shown in Table 10 along with the VLII parameter in the REG-RSP message corresponding to the REG-REQ message send. As an example, the following parameters, namely the Timer_in_MS_for_New_SLM parameter, have a TLV encoding type.

The Timer_in_MS_for_New_SLM parameter contains the same value as requested by the MS through the MOB_SLP-REQ message, or a value assigned within the tolerance range supported by the BS. At this time, the value of the Timer_in_MS_for_New_SLM parameter is set to a value larger than the value of the Timer_in_BS_for_New_SLM timer managed by the BS.

On the other hand, when the BS transmits the REG-RSP message to the MS and includes only the VLII and does not include the Timer_in_MS_for_New_SLM parameter, the MS decides to drive the Timer_in_MS_for_New_SLM timer to a preset value.

The Timer_in_MS_for_New_SLM timer can be set differently for each power saving class. That is, the Timer_in_MS_for_New_SLM timer can be set to a value different for each data pattern belonging to each power saving class, that is, connection. Table 11 shows the parameter formats for supporting different Timer_in_MS_for_New_SLM timers according to power saving classes.

The parameters shown in Table 11 are used only for the power saving class whose TTWF is set to '0' in the MOB_SLP-REQ message and the MOB_SLP-RSP message when the MS and the BS can perform or support a new sleep mode . At this time, the MS may set the Timer_in_MS_for_New_SLM parameter to a default value, and the BS may request a desired value.

In another embodiment, the VLII parameter may be included in the MOB_SLP-REQ message and the MOB_LSP-RSP message in a parameter format other than the TLV encoding format. At this time, the Timer_in_MS_for_New_SLM timer can be transmitted in a TLV encoding format as shown in Table 12 below. That is, the VLII parameter can be transmitted in IE format, and the Timer_in_MS_for_New_SLM timer can be transmitted in TLV encoding format.

At this time, the BS sets the value of the Timer_in_MS_for_New_SLM timer managed by the MS including the 'TLV encoded information' as shown in Table 12 for the power saving class set to '0' in TTWF and the power saving class set in 'VLII' .

The following embodiments are proposed to solve the problem that occurs when the MS and the BS simultaneously request the sleep mode. That is, the following parameters are added to the MOB_SLP-RSP message in addition to the parameters shown in Table 2 in order to distinguish the MOB_SLP-REQ message transmitted by the MS in the non-request method of the BS.

- Unsolicited Indication

The unsolicited indication parameter is set to '1' when the BS transmits the MOB_SLP-RSP message to the MS in a non-request manner.

In another embodiment, instead of Sleep_Approved described in Table 2, the following parameters are included in the MOB_SLP-RSP message.

- Response code (Response_Code)

The response code parameter indicates whether the MOB_SLP-RSP message is a response to an MS request or an unsolicited request. In other words, when the value of the response code is '0', it means that the BS transmits the MOB_SLP-RSP message to the MS in an unsolicited manner. If the response code is '1', the MS acknowledges the MOB_SLP- , And if it is '2', it indicates rejection of the MOB_SLP-REQ message transmitted by the MS.

Other types of unsolicited indication parameters other than those mentioned above may be used to indicate that the MOB_SLP-RSP message is transmitted in an unsolicited manner. If it is determined by the unsolicited instruction parameter that the MS and the BS have requested the sleep mode at the same time, either one of the following operations can be performed according to the system setting, the system designer's selection, the definition of the standard, or other criteria .

First, when the request of the MS is prioritized, the BS ignores the unsolicited MOB_SLP-RSP message sent by the BS and responds to the MOB_SLP-REQ message of the MS. The MS also ignores the MOB_SLP-RSP message of the unsolicited scheme and waits for the BS to retransmit the appropriate MOB_SLP-RSP message for its MOB_SLP-REQ message.

Next, when priority is given to the request of the BS, the BS considers the MS to abandon the MOB_SLP-REQ message sent by the MS and perform the sleep mode operation according to the MOB_SLP-RSP message of the BS. The MS operates according to the parameters of the unsolicited MOB_SLP-RSP message sent by the BS.

In the modified embodiment described later, the conditions for terminating the variable listening interval are independently defined by the BS and the MS. That is, the driving conditions of the timers for extending the listening interval are as follows.

- The driving condition of Timer_in_MS_for_New_SLM

In the above-described second embodiment, when the MS receives the DL data from the BS during the listening interval or receives a positive indication through the MOB_TRF-IND message, the MS has driven the timer at the end of the listening interval. On the other hand, in the following embodiments, the MS receives DL data from the BS during the listening interval, or performs signaling (e.g., included in the DL-MAP message instructing downlink resource allocation of each frame) informing the MS of transmission of DL data A DL-MAP IE indicating that the DL data is transmitted to the MS or receives a positive indication via the MOB_TRF-IND message. The reason for using signaling to notify the transmission of the DL data instead of receiving the actual DL data is as follows. Even if the MS receives the DL-MAP informing that the DL data is transmitted, This is to prepare for the case of failing to decode the burst. For example, when a BS allocates a resource for a DL burst through a DL MAP to an MS, even if the MS fails to decode the DL burst, the base station retransmits the DL burst according to a Hybrid Automatic Repeat request (HARQ) , The MS does not enter the sleep state and waits for retransmission of the DL burst according to the signaling.

The condition under which the timer is reset is the same as in the second embodiment. Additionally, the timer is reset when receiving an ARQ ACK or HARQ ACK for UL traffic. If a NACK-based ARQ scheme is used, ARQ NACK, rather than ARQ ACK, is used to reset the timer, and if NACK-based HARQ scheme is used, HARQ NACK is used to reset the timer. Further, the MS resets the timer when receiving signaling (e.g., resource allocation information indicating that the DL data is transmitted to the MS included in the DL-MAP message) indicating transmission of DL data to the MS . Therefore, even if the MS fails to decode the DL burst indicated by the DL-MAP IE, the MS does not enter the sleep state according to the signaling.

As a result, the listening interval is extended if the MS can know that the BS is operating normally.

- Driving condition of Timer_in_BS_for_New_SLM

In the above-described second embodiment, when the BS receives the UL data from the MS during the listening interval, the BS drives the timer at the end of the listening interval. On the other hand, in the following embodiment, the BS directly drives the timer when the BS receives the UL data from the MS during the listening interval.

The condition under which the timer is reset is the same as in the second embodiment. Additionally, the timer is reset when receiving an ARQ ACK or HARQ ACK for DL traffic. If a NACK-based ARQ scheme is used, an ARQ NACK other than ARQ ACK is used to reset the timer, and if a NACK-based HARQ scheme is used, HARQ NACK is used to reset the timer. As a result, the listening interval is extended if the BS can know that the MS is operating normally.

In the modified embodiment described below, the conditions for transiting to the sleep state with respect to the timers for extending the listening interval are defined as follows.

- Sleep condition transition condition by Timer_in_MS_for_New_SLM

In the above-described second embodiment, when the timer Timer_in_MS_for_New_SLM timer expires, the MS transits to the sleep state if there is no data to be transmitted to the BS. However, in this case, if UL traffic continues to exist in the MS, the MS will always stay awake and the battery consumption of the MS will be increased. Therefore, in the following embodiment, the MS transits to the sleep state when the timer expires and the number of retransmission retries or the number of retransmission attempts of the ARQ is exhausted. Therefore, the presence or absence of UL traffic to be transmitted by the MS does not affect the sleep state transition of the MS. That is, when the retransmission attempt expires, the MS is in a state in which it can not properly receive an ACK from the BS, that the DL traffic does not exist, and the MS transitions to the sleep state. Here, when the number of retransmissions reaches a predetermined maximum limit, the MS determines that the number of retransmission attempts has expired.

- Sleep condition transition condition by Timer_in_BS_for_New_SLM

Meanwhile, the BS waits until the HARQ or ARQ retransmission attempt expires when the Timer_in_BS_for_New_SLM timer expires. Thereafter, when the number of HARQ retransmission attempts or the number of ARQ retransmission attempts expires, it is regarded that the MS transitions to the sleep state. Likewise, the presence or absence of the DL traffic to be transmitted to the MS by the BS does not affect the condition that the MS regards as a transition to the sleep state.

In another modified embodiment, the driving conditions of the timers for extending the listening interval are defined as follows.

If the MS receives DL data from the BS during the listening interval or receives an ACK (HARQ ACK or ARQ ACK) for the UL data, the MS immediately starts the Timer_in_MS_for_New_SLM timer. The BS directly receives the UL data from the MS during the listening interval or the Timer_in_BS_for_New_SLM timer when receiving the ACK for the DL data.

In another modified embodiment, the driving conditions of the timers for extending the listening interval are defined as follows.

When the MS receives DL data from the BS during the listening interval or receives an ACK (HARQ ACK or ARQ ACK) for UL traffic, or transmits a BW-REQ to the BS, the UL allocates an UL burst as a grant (GRANT) Timer_in_MS_for_New_SLM timer is started immediately when received. When the BS receives the UL data from the MS or receives an ACK (HARQ ACK or ARQ ACK) for the DL traffic during the listening interval, or receives the BW-REQ from the MS and allocates the UL burst as a grant to the MS, the Timer_in_BS_for_New_SLM Run the timer immediately.

As another modified embodiment, in addition to the above-mentioned driving conditions for the timer for the extension of the listening interval, the MS considers the case of receiving a positive indication from the BS via the MOB_TRF-IND message. That is, if the MS receives a positive indication from the BS via the MOB_TRF-IND message, it directly drives the Timer_in_MS_for_New_SLM timer.

In a modified embodiment of the present invention, when the BS does not have any DL traffic to be transmitted to MSs expected to transmit a MOB_TRF-IND message during the listening interval and thus does not transmit the MOB_TRF-IND message, The following fields are included in the DL-MAP message in order to inform the user.

- Transmission_of_MOB_TRF-IND

If the field is set to '0', it means that the BS does not transmit the MOB_TRF-IND message, that is, there is no DL traffic to the MSs waiting to receive the MOB_TRF-IND message while awake during the listening interval . If there is no UL traffic, the MSs aware of the field transit to the sleep state immediately, regardless of the length of the remaining listening interval, and wake up again in the next listening interval. If the field is set to '1', the MSs wait for reception of the MOB_TRF-IND message as in the existing operation.

The field may be transmitted in a TLV encoding format in the DL-MAP or in a 1-bit indicator format inserted in the super frame header.

If the MS wakes up from sleep mode, it is necessary to check the frame number to see if it wakes up from the correct frame. When a super frame is used and one super frame is composed of a plurality of frames, the frame number or the super frame number is confirmed only through the super frame header located in the first frame of the super frame. However, when the sleep mode operation is performed on a frame-by-frame basis, the MS can not immediately receive the superframe header, and the frame number may not be known. Therefore, when a superframe structure is used, the sleep mode operation must be performed on a superframe basis (Super Frame basis). That is, the listening interval must be located from the first frame of the superframe. However, the length of the listening interval does not have to be long in multiples of the superframe.

To this end, the start_frame_numbe indicating the position of the frame in which the sleep interval starts in the MOB_SLP-REQ / RSP message is set to indicate the first frame of the superframe. As an example, the start_frame_number is set to 6 bits of LSB (Least Significant Bit) of the super frame number identifying the super frame, or 6 bits of the LSB of the frame number that identifies the first frame of the super frame.

In addition, the unit size of the sleep interval is [superframe length x N]. Here, the superframe length means the number of frames included in one superframe, for example, four frames. Therefore, N or 4xN is included in the "initial-sleep window" field or other field of the MOB_SLP-REQ / RSP message to indicate the length of the sleep interval.

When one sleep interval and one sleep interval are called a sleep cycle in the sleep mode, the sleep interval is included in each sleep cycle. Therefore, if the start position of the sleep interval, which is the start of the sleep cycle, is designated as the first frame of the superframe and the unit length of the sleep interval is designated as a multiple of the superframe length, even if the length of the sleep interval doubles, It is always located in the first frame of a superframe. Accordingly, the MS can refer to the frame number to confirm that the awake point of the MS is awake when awakened from the listening interval.

According to the new sleep mode operation of the present invention, while continuing to receive data or receive an ACK, the listening interval is extended by the timers running in the BS and the MS. In this case, the extended listening interval may eventually reach the next scheduled listening window (Next Scheduled Listening Window). This means that the timers of both BS and MS have been continuously reset due to data and / or ACK. Then, the MS and BS determine that the extended listening interval has ended and apply the new sleep mode operation again in the next scheduled listening interval. The next scheduled listening interval may be a new extended listening interval depending on the result of the application. Here, the scheduled listening interval means a listening interval originally determined by the parameters indicated by the MOB_SLP-REQ / RSP message.

In particular, since the length of the sleep interval is relatively short at the beginning of the sleep mode operation, there is a high probability that the extended listening interval will reach the next scheduled listening interval. If the extended listening interval is terminated and the newly started listening interval is repeated several times in succession, that is, if the extended listening interval occurs consecutively several times, the MS continuously maintains the sleep mode It becomes meaningless.

Therefore, in the embodiment described below, a threshold value for checking the number of consecutive extended listening intervals is used. The MS determines whether the number of consecutive extended listening intervals has reached the threshold value when the extended listening interval reaches the next scheduled listening interval according to the new sleep mode operation of the present invention. Wherein the new extended listening interval is included or omitted in counting the number of consecutive extended listening intervals. If the number of consecutive extended listening intervals is less than the threshold value, the MS maintains the sleep mode. On the other hand, if the number of consecutive extended listening intervals reaches the threshold value, the MS determines that the sleep mode is no longer needed and transitions from the sleep mode to the normal mode. The BS also recognizes, via an algorithm similar to that of the MS, whether the MS remains in the sleep mode or transitions to the normal mode.

If the next scheduled listening interval is reached without transition to the normal mode, the timers used for extending the listening interval are restarted after being stopped. For example, if a data exchange occurs in a situation where the timer is stopped, the timers for extending the listening timers are restarted by the conditions described in the aforementioned embodiment.

Another embodiment of the present invention will be described below. The sleep cycle consists of a listening interval and a sleep interval. However, the initial sleep cycle does not include the listening interval, and is the sum of the listening interval and the sleep interval from the second sleep cycle. If there is no exchange of data traffic between the subscriber station and the base station during the listening interval included in the previous sleep cycle or a negative indication is included in the traffic indication (TRF-IND) message, the current sleep cycle length may be changed to twice the previous sleeping period have. However, the length of the current sleep cycle can not exceed a predetermined maximum sleep cycle. Also, even if the current sleep cycle doubles, the listening interval in the current sleep cycle is not doubled.

On the other hand, if there is a data exchange in the listening interval of the previous sleep cycle or a positive indication is included in the traffic indication (TRF-IND) message, the current sleep cycle is initialized to the initial sleep cycle. However, if the length of the initialized current sleep cycle is smaller than the listening interval, the current sleep cycle can not include the listening interval. Therefore, when resetting each sleep cycle, the following conditions are additionally considered.

Current Sleep Cycle = Initial Sleep Cycle

  If 'Current Sleep Cycle' = <Listening Window

    Current Sleep Cycle = 2 x Initial Sleep Cycle

  Else

    Current Sleep Cycle = Current Sleep Cycle

That is, when the current clock is larger than the listening interval, the sleep cycle is maintained at the previous value.

Brief Description of the Drawings Fig. 1 shows an operation for performing an operation for a sleep mode of a communication system; Fig.

2 is a diagram illustrating an operation for a BS to transmit data in a communication system according to an embodiment of the present invention;

3 is a diagram illustrating an operation for an MS to transmit data in a communication system according to an embodiment of the present invention;

4 is a diagram illustrating an operation of the MS related to a sleep mode in a communication system according to an embodiment of the present invention;

5 is a diagram illustrating a sleep mode related operation of a BS according to an embodiment of the present invention;

Claims (20)

A communication method of a terminal (MS) in a communication system, Starting a timer for a listening interval corresponding to a listening state when the mobile station receives at least one of first signaling information and data indicating a data transmission on a first allocated resource from a base station, When the UE receives second signaling information indicating data transmission on a second allocated resource from the base station, re-driving the timer to extend the listening interval; Maintaining the listening state by extending the listening interval until the timer expires; And transitioning to a sleep state when the timer expires. The method according to claim 1, (SLP_REQ) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable to the base station, / RTI &gt; The method according to claim 1, Receiving a sleep response (SLP_RSP) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable from the base station, / RTI &gt; 4. The method of claim 3, wherein the sleep response (SLP_RSP) And a third parameter indicating whether the sleep response message is transmitted in response to the sleep request message transmitted by the terminal or in an unsolicited manner other than a response to the sleep request message The sleep mode control method comprising: The method according to claim 1, The terminal operates a sleep cycle including a sleep interval corresponding to the sleep interval and the listening interval, The length of the sleep cycle is set to a value that indicates that there is no exchange of data traffic between the UE and the BS during a previous listening interval included in a previous sleep cycle or a negative indication is included in a TRF- , Twice the length of the previous sleep cycle, Wherein a length of the listening interval included in the sleep cycle is maintained equal to the previous listening interval. A method for controlling communication of a terminal (MS) in a communication system,  Starting a timer for a listening interval corresponding to a listening state when at least one of first signaling information and data indicating a data transmission on a first allocated resource is transmitted to the mobile station by the base station, When the base station transmits second signaling information for instructing data transmission on a second allocated resource to the terminal, re-driving the timer to extend the listening interval; Determining that the terminal is maintaining the listening state by extending the listening interval until the timer expires; And determining that the UE transitions to a sleep state when the timer expires. The method according to claim 6, (SLP_REQ) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable, from the terminal, / RTI &gt; The method according to claim 6, (SLP_RSP) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval can be extended, to the terminal / RTI &gt; The method of claim 8, wherein the sleep response (SLP_RSP) And a third parameter indicating whether the sleep response message is transmitted in a response to the sleep request message received from the terminal or in an unsolicited manner other than a response to the sleep request message The sleep mode control method comprising: The method according to claim 6, The terminal operates a sleep cycle including a sleep interval corresponding to the sleep interval and the listening interval, The length of the sleep cycle is set to a value that indicates that there is no exchange of data traffic between the UE and the BS during a previous listening interval included in a previous sleep cycle or a negative indication is included in a TRF- , Twice the length of the previous sleep cycle, Wherein a length of the listening interval included in the sleep cycle is maintained equal to the previous listening interval. A terminal apparatus in a communication system, A controller for re-driving a timer for a listening interval corresponding to a listening state when the mobile station receives at least one of first signaling information and data indicating a data transmission on a first allocated resource from a base station; And a transceiver for maintaining the listening state by extending the listening interval until the timer expires, and transiting to a sleep state when the timer expires. 12. The transceiver of claim 11, (SLP_REQ) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable to the base station. 12. The transceiver of claim 11, And a sleep response (SLP_RSP) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable, from the base station. 14. The method of claim 13, wherein the sleep response (SLP_RSP) And a third parameter indicating whether the sleep response message is transmitted in response to the sleep request message transmitted by the terminal or in an unsolicited manner other than a response to the sleep request message . 12. The method of claim 11, The terminal operates a sleep cycle including a sleep interval corresponding to the sleep interval and the listening interval, The length of the sleep cycle is set to a value that indicates that there is no exchange of data traffic between the UE and the BS during a previous listening interval included in a previous sleep cycle or a negative indication is included in a TRF- , Twice the length of the previous sleep cycle, Wherein the duration of the listening interval included in the sleep cycle is maintained equal to the previous listening interval. A base station apparatus for controlling communication of a terminal (MS) in a communication system,  The base station starts a timer for a listening interval corresponding to a listening state when at least one of first signaling information and data indicating a data transmission on a first allocated resource is transmitted to the mobile station, When the second signaling information indicating the data transmission on the second allocated resource is transmitted to the terminal, the timer is restarted to extend the listening interval, and the terminal extends the listening interval until the timer expires A controller that determines that the subscriber station is in the listening state and determines that the subscriber station transitions to a sleep state when the timer expires; And a transceiver for exchanging data and messages with the terminal under the control of the controller. 17. The transceiver of claim 16, (SLP_REQ) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval can be extended, from the terminal. 17. The transceiver of claim 16, (SLP_RSP) message including a first parameter indicating a default length of the listening interval and a second parameter indicating whether the listening interval is extendable to the terminal. 19. The method of claim 18, wherein the sleep response (SLP_RSP) And a third parameter indicating whether the sleep response message is transmitted in a response to the sleep request message received from the terminal or in an unsolicited manner other than a response to the sleep request message The base station apparatus comprising: 17. The method of claim 16, The terminal operates a sleep cycle including a sleep interval corresponding to the sleep interval and the listening interval, The length of the sleep cycle is set to a value that indicates that there is no exchange of data traffic between the UE and the BS during a previous listening interval included in a previous sleep cycle or a negative indication is included in a TRF- , Twice the length of the previous sleep cycle, Wherein a length of the listening interval included in the sleep cycle is maintained equal to the previous listening interval.

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